This is a trick that can be used to multiply two numbers by drawing out lines and counting crossings. In this version you can use numbers with up to 3 digits. Try it out and see if you can do it yourself with 2 digits numbers. For example you can try 13 x 21. I know the counting a little slow. Try turbo mode if you get impatient (hold shift and click the green flag).
Holy Addition Batman!! Featured on 2014-11-20. Thanks for all your messages people, I read them even if I don't answer them all. Here is an example done by hand: https://www.youtube.com/watch?v=kzEOcZ-oulc